Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to techniques for receiving uplink signals in self-organizing cellular wireless networks.
Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
A wireless communication network may include a number of base stations that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station. A base station may be, or may include, a macrocell or microcell. Microcells are characterized by having generally much lower transmit power than macrocells, and may often be deployed without central planning. In contrast, macrocells are typically installed at fixed locations as part of a planned network infrastructure, and cover relatively large areas.
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) advanced cellular technology as an evolution of Global System for Mobile communications (GSM) and Universal Mobile Telecommunications System (UMTS). The LTE physical layer (PHY) provides a highly efficient way to convey both data and control information between base stations, such as an evolved Node Bs (eNBs), and mobile entities, such as UEs. In prior applications, a method for facilitating high bandwidth communication for multimedia has been single frequency network (SFN) operation. SFNs utilize radio transmitters, such as, for example, eNBs, to communicate with subscriber UEs.
Wireless networks have seen increasing addition of small, low-power cells such as femto cells and pico cells. Many small cells are deployed on an ad hoc basis and are interconnected with macrocells making up planned wireless infrastructure. Management techniques for self-organizing networks of small cells (e.g., Qualcomm's (UltraSON)) may require uplink (UL) signal sensing by the small cell to manage transmission (TX) power levels of the small cell and its associated beacons. In UL sensing, the small cell measures the power of UL signals from access terminals in the vicinity, whether or not connected to the small cell. The small cell may then adjust its transmission power accordingly.
Measurement of UL signals on different carrier frequencies by the small cell requires use of small cell receiving (RX) resources. To avoid using a dedicated set of RX resources for UL sensing, prior solutions called for using a wide band analog low pass filter (LPF) in the receiver. The wide band LPF passed multiple UL signals in adjacent carriers for power management, enabling UL signal measurement without requiring use of a dedicated, separate RF receiving path for each UL measurement. However, this approach may not be optimal for next-generation networks that include broader base station classifications with higher TX power levels and more stringent minimum performance specifications (MPS), for example for adjacent channel (ACS) or “blocker” channel (±10 MHz, UMTS) cells. Such scenarios may place more stringent requirements on analog filtering and analog-to-digital conversion (ADC) dynamic range to avoid ADC saturation. Accordingly, new approaches for UL signal measurement by nodes of self-organizing networks (e.g., femtocells or Home NodeB's) are desired.